liunx 下 Python2升级到Python3完整教程

安装Python3：

yum install gcc gcc-c++ libffi-devel python-setuptools vim wget make sqlite-devel zlib* bzip2-devel openssl-devel ncurses-devel readline-devel tk-devel -y
cd /opt
wget https://mirrors.huaweicloud.com/python/3.9.6/Python-3.9.6.tar.xz

先 xz -d Python-3.9.6.tar.xz 将 Python-3.9.6.tar.xz解压成 Python-3.9.6.tar

然后再用 tar xvf Python-3.9.6.tar来解包

cd /opt/Python-3.9.6
./configure --with-ssl
make
make install

 

设置默认版本：

mv /usr/bin/python /usr/bin/python.bak
ln -s /usr/local/bin/python3 /usr/bin/python

 

修复yum配置：

修改​​/usr/bin/yum​​和​​/usr/libexec/urlgrabber-ext-down​​，将​​#!/usr/bin/python​​改为​​#!/usr/bin/python2.7​​，保存退出即可。

升级pip：

pip3 install --upgrade pip

 

解决root用户执行pip3命令时提示警告的问题：

[root@cch-spider-web1 ~]# pip3 install --upgrade pip
Looking in indexes: http://mirrors.aliyun.com/pypi/simple/
Requirement already satisfied: pip in /usr/local/lib/python3.9/site-packages (21.1.3)
WARNING: Running pip as the 'root' user can result in broken permissions and conflicting behaviour with the system package manager. It is recommended to use a virtual environment instead: https://pip.pypa.io/warnings/venv

改为执行时带上--user参数：

pip3 install --user packagename

 

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